<b>Radiation studies</b><br>We are conducting an ongoing screening study of Ukraine and Belarus residents exposed under age 18 yr to radioactive nuclides, especially I-131, released during the Chornobyl nuclear reactor accident. We found urinary iodine levels consistent with mild to moderate iodine deficiency; however, evidence suggested urinary iodine levels have increased in recent years. In an ecological study in Northern Ukraine, we estimated an excess RR/gray of 8.0 and an excess absolute risk per 10,000 person-year-gray of 1.5, which were compatible with external radiation exposure.<br><br>We studied the dose-response for acoustic neuroma incidence in a cohort of 3112 individuals irradiated as children between 1939-1962 and found an association with childhood radiation exposure.<br><br>Thyroid cancer risk increases with age at radiation exposure, particularly under age 20, perhaps reflecting increased cell proliferation. We measured the Ki-67 proliferative index in 117 thyroid glands obtained at autopsy, including fetal, child and adult thyroids, and found a reduced index with age, consistent with higher radiation-related thyroid cancer risks in children compared to adults.<br><br><b>Cancer risks among formaldehyde workers</b><br>We found exposure-response relationships for leukemia and nasopharyngeal cancer, but no association with pancreas, brain, lung or prostate cancers in a cohort of formaldehyde workers.<br><br><b>Studies of pesticide exposures</b><br>We evaluated the use of crop maps for predicting herbicides in carpet dust samples as a measure of exposure and found that crop maps useful for estimating herbicide levels for rural residents exposed through proximity of their homes to crop fields.<br><br>We conducted a nested casecontrol study of liver cancer in participants of the Nutritional Intervention Trials in Linxian, China and found an increased risk with serum DDT, but not serum DDE, concentration.<br><br><b>Liver cancer and folate levels</b><br>We examined folate levels in blood and risk for subsequent liver damage and hepatocellular carcinoma in 415 hepatitis B surface antigenpositive participants of the Haimen City Cohort. Higher RBC folate levels were associated with reduced risk of hepatocarcinogenesis.<br><br><b>Testicular Cancer</b><br>We studied testicular germ cell tumors (TGCT) in the Servicemen's Testicular Tumor Environmental and Endocrine Determinants (STEED) study and found increased height significantly related to risk. There was no association with BMI, measures of age at puberty or dairy consumption. We also evaluated 32 SNPs in 16 immune function genes; however, none of the associations were noteworthy after controlling for multiple testing. We found no relationship between passive smoking, either in utero or in childhood, and risk of TGCT.<br><br>We analyzed maternal hormone levels and various surrogates in the Collaborative Perinatal Project and found that maternal height, weight, BMI, gestational age, son's birth weight, length and head circumference varied with levels of testosterone, estradiol and estriol differently in Whites and Blacks. This suggested that surrogates for perinatal hormone levels should be ethnic group specific.<br><br><b>Non-Hodgkin lymphoma</b><br>We investigated the relationship between high-density lipoprotein cholesterol (HDL-C) and NHL in the ATBC Cancer Prevention Study and found no association between total or non-HDL cholesterol and NHL cases, but an inverse association between HDL-C and NHL.<br><br><b>Studies of viruses</b><br>Persistent infection with carcinogenic HPV causes cervical precancer. We found that subgroups of HPV type, carcinogenicity, or phylogenetic species have significantly different HPV persistence, with phylogenetic species the best predictor of HPV persistence.<br><br>We conducted a case-cohort study of H. pylori seropositivity and esophageal and gastric cancers in residents of Linxian, China. Risks of both gastric cardia and non-cardia cancers increased with H. pylori exposure, whereas risk of esophageal squamous cell cancer was not affected. The associations between H. pylori exposure and gastric cardia and non-cardia adenocarcinoma were comparable, in contrast to Western countries.<br><br>We measured various biomarkers in HTLV-I carriers and HTLV-I negative subjects. Carriers had higher cleaved lymphocytes, WBCs and phosphorus levels. In carriers, antibody titer was positively correlated with lactate dehydrogenase (LDH) and phosphorus levels. Provirus load among carriers was negatively correlated with hemoglobin and eosinophil proportion, and positively correlated with phosphorus. Stercoralis antibodies were not associated with HTLV-I status, antibody titer, or provirus load.<br><br>We assessed Kaposi sarcoma-associated herpes virus (KSHV) transmission from mothers to children and HIV status. Risk of KSHV acquisition was higher in children of KSHV-seropositive mothers. However, HIV status of the mother was only marginally associated with an increased risk of KSHV seropositivity in the child.<br><br>We reconstructed HCV incidence in White males with hemophilia A in a U.S. hemophilia population to evaluate time trends. Results suggested that interventions since 1970, particularly donor deferral, HBV and HIV screening, and viral inactivation of clotting factor concentrates, reduced transfusion of HCV after its discovery.<br><br><b>Biomarkers</b><br>We analyzed 17 candidate markers related to hormonal pathways for invasive breast cancers from a population-based case-control study. Our goals were to assess marker co-expression patterns and relate them to tumor characteristics and risk factors.<br><br>Using DCEG volunteers, we studied the performance of several urine pH strips and the influence of subject characteristics and measurement conditions to improve the measurement of urine pH levels in epidemiologic studies.<br><br><b>Cancer Risks in Persons at Genetic Risk of Cancer</b><br>Severe Congenital Neutropenia (SCN) is a bone marrow failure syndrome that predisposes acute myeloid leukemia. SCN is genetically heterogeneous, with most cases attributed to autosomal dominant mutations in the ELA2 gene. We found that both wild and mutant types of SCN patients had high risk of leukemia, with a 34% cumulative incidence after 15 years of follow-up.<br><br>Fanconi Anemia (FA) is an inherited bone marrow failure syndrome. We evaluated bone marrow failure and cancer outcome in a large cohort of FA patients from Germany (the GEFA cohort). We found that FA was both an inherited bone marrow failure syndrome and a highly penetrant cancer susceptibility syndrome with early onset of AML and later onset of specific solid tumors.<br><br><b>Analyses of diet and nutrients in national surveys</b><br>We analyzed Black/White differences in serum selenium from the Third National Health and Nutrition Examination Survey (NHANES). Concentrations were higher in Whites than Blacks, which may help explain racial disparities in incidence of prostate and other cancers. We examined dietary trend data from four NHANES surveys. Energy intake, food amount and carbohydrate energy increased, whereas percent of energy from protein, fat and saturated fat decreased over time in all race and gender groups. Blacks reported lower intakes of vegetables, potassium and calcium than Whites. Results suggested that dietary risk factors that differentially affect Blacks have not improved relative to Whites. Using NHANES I, II, and III, we examined poverty income ratio, education, diet and biomarkers of diet and disease, as measures of socioeconomic position, and found a persistence of unfavorable dietary and biomarker profiles with low income and education.<br><br